Neutronics Design And Study On Subcritical Spent Fuel Burner

Shortage of nuclear resources, spent fuel handling, nuclear safety and nonproliferation restrict the development of nuclear energy. There are many advantages of subcritical reactor because with good safety characteristic and suitable for spent fuel handling, etc.Neutronics design and research of a fusion/accelerator driven subcritical spent fuel burner for nuclear waste transmutation, fissile fuel breeding and energy production was presented based on investigation and analysis of the existing subcritical research, and a comparative study between fusion driven subcritical reactor and accelerator driven subcritical reacor have been done. Fusion/Acceletator driven subcritical reactor makes use of spent nuclear fuel (SNF) from Pressurized Water Reactor (PWR) as fuel, it’s designed based on relatively easy-achieved fusion-drive or accelerator-drive technology and the subcritical blanket is designed based on the well-developed technologies of fission reactor. In this contribution, the main research contents including:1) Neutron source analysis and optimization of the fission blanket which focused on fuel composition, blanket structure, depleted uranium layer and the operating mode of two types of subcritical spent fuel burner (fusion driven spent fuel burner and accelerator driven spent fuel burner) were presented. Based on the results of optimization, the burnup analysis, activation characteristics analysis and analysis of material radiation damage have been carried out.2) Comparative study in energy balance, safety characteristic between the fusion driven subcritical reactor and accelerator driven subcritical reactor was carried out. the unique safety issues are discussed, and based on the design of fusion/accelerator driven spent fuel burner, and the evaluation of neutronics performance was achieved.Based on the above research, under consider of a series of safety constraints and engineering constraints, the fusion driven subcritical spent fuel burner can achieve the energy gain～10.2GWth, the Tritium Breeding Ratio (TBR)～2.36, the Breeding Support Ratio (BSR)～2.12, the Transmutation Support Ratio (TSR)～3.76, annual output of tritium～865g, the actinide transmutation fration～19.3%and burnup～83.8GW.d/t after10years of continuous operation. For the accelerator driven subcritical spent fuel burner, the energy gain～432MWth, the Breeding Support Ratio (BSR)～0.19, the Transmutation Support Ratio (TSR)～0.16, the actinide transmutation fration～30.7%and burnup～91.1GW.d/t after10years of continuous operation. The comparative studies show that fusion driven subcritical reactor is better in energy balance than accelerator driven subcritical reactor, but the latter have better safety design potential. There are similar neutronics performances of the neutron spectrum, capture/fission cross section ratio and effective half-life, but accelerator driven subcritical spent fuel burner have better performance in biohazard factor, neutron balance, the efficiency of the source neutrons, breeding ratio, future development capacity and minor actinide loss rate.